The Minnesota Community Prevention Program (MCPP) proposes a unique and concentrated demonstration approach to the primary prevention of premature heart attack and stroke in selected Minnesota communities. It is based on the important influence of several cardiovascular risk factors, and much evidence that they can safely be modified. These risk factors include elevated blood pressure, cigarette smoking, a habitual diet common in this country resulting in mass hyperlipidemia, along with physical inactivity. The MCPP strategy employs community-wide education in a sequential comparison of experience in selected pairs of Minnesota communities. One community is observed and one organized for a long-term, multiple factor, multiple strategy effort in health education. Tactics include a) direct "hands-on" education, b) professional education to enhance prevention services, c) organization and training of community leaders, d) mass communications, and e) enhanced community support for healthy behavior. The strong components herein of design, methods development, and of evaluation of the educational program are all essential to produce new knowledge in this early period of national concern for prevention and health promotion. This public health trial or demonstration uses optimally a host of existing facilities in Minnesota and a long experience in community studies, risk reduction trials, and extension education. The MCPP plans to leave, on completion of the research and development, well established mechanisms to maintain a more healthy behavior in Minnesota communities. It is designed to demonstrate new and important issues for the future of preventive efforts in the public health.